A network switch creates a network among a plurality of end nodes, such as workstations, and other network switches connected thereto. Each end node is connected to one port of the network. The ports also serve to connect network switches together.
Each end node sends packets of data to the network switch which the switch then routes either to another of the end nodes connected thereto or to a network switch to which the destination end node is connected. In the latter case, the receiving network switch routes the packet to the destination end node.
Each network switch has to temporarily store the packets of data which it receives from the units (end node or network switch) connected to it while the switch determines how, when and through which port to retransmit the packets. Each packet can be transmitted to only one destination address (a "unicast" packet) or to more than one unit (a "multicast" or "broadcast" packet). For multicast and broadcast packets, the switch typically stores the packet only once and transmits multiple copies of the packet to some (multicast) or all (broadcast) of its ports. Once the packet has been transmitted to all of its destinations, it can be removed from the memory or written over.
Switching Ethernet controllers are network switches that implement the Ethernet switching protocol. According to the protocol, the Ethernet network (cabling and Ethernet ports) operates at 10 Megabits per second. However, most switches do not operate at that speed, since they require longer than the 10 Mbps to process the incoming packets. Thus, their throughput is less than 10 Mbps. Switches which do operate at the desired speed are known as providing "full-wire" throughput.